Pipe plug



SePt- 13, 1933- J. F. RICHARDSON 2,130,030

PIPE PLUG Filed Aug. e, 195e .1. 1\.5 131.@ 161514.17161L/1o 121 2 l Summa Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to improvements in pipe plugs and its objects are as follow:

First, to provide a plug for stopping up a pipe or other conductor which is suspected of having a leak, so as to conne the pressure fluid, whether liquid or gas, to the affected area and thus more readily discover the place where the leak is located, said plug including an elastic sleeve which is expanded by some externally applied pressure fluid into intimate contact with the bore of the pipe to form a seal.

Second, to make the vent holes in the tubular core of inwardly tapering shape so that none of the pressure iiuid will be trapped behind the elastic sleeve to prevent its return to the original position when the pressure is let down.

Third, to vulcanize the ends of the elastic sleeve to the end fittings to make absolutely tight joints past which pressure uid cannot escape.

Fourth, to provide the plug with pipe couplings which enable the making of a joint outside of the end cups or fittings, said couplings further serving to protect the threads as is pointed out below.

Other objects and advantages will appear in the following specification, reference being had to the accompanying drawing, in which:

Figure 1 is a partial sectional and elevational view showing the improved plug in an operative position in a pipe to be tested.

Figure 2 is a longitudinal section of the pipe plug in its normal condition.

Figure 3 is a cross section taken on the line 3 3 of Figure 2.

'I'he purpose of the instant pipe plug is to quickly and effectively stop the flow of any gas or liquid, usually under pressure, through virtually any kind of a conductor, whether straight or curved. A section of such a conductor, herein designated the pipe, is indicated I. This pipe is suspected of having a leak and the plug, generally designated 2, is set in position in the pipe preparatory to making a test for the leak. The suspected area is regarded as being at the left of the plug.

The plug comprises a center tube 3 which is externally threaded on each of its ends as at 4. Ordinary pipe couplings 5, 6 are screwed onto these threaded ends and one or the other of the pipe couplings is used for the fastening on of some kind of a contrlvance for pushing the plug 2 into the desired position into the pipe I. Such a contrivance is indicated by the dotted lines 1, and it may consist either of a iiexible (Cl. 13S-93) hose, which will enable pushing the plug around bends, or it may be a rigid tube or rod. The other end is either sealed by a pipe plug Ia or tted to another and similar pipe plug by exible rubber hose or solid iron pipe.

It is necessary to end the contrivance 1, if of tubular form, with a check valve 8 which has any suitable means whereby a tube may be attached for the supply of pressure iiuid, for example the nipple 8. As seen in Fig. 2, the ccntrivance 1 is screwed into the coupling 6, and said contrivance 1 together with its check valve 8 comprise the outside closure means for the pipe plug. The companion coupling 5 is closed by the previously mentioned plug 1a in order to conne the pressure fluid admitted through the check valve 8a. The contrivance 1 can be screwed into the coupling 5, in which event the coupling 6 would be closed by screwing the plug 1n into said coupling 6.

One or more holes 9 in the center tube 3 provide for the escape of pressure uid into an internal chamber I0 defined by the tube 3, a concentric but spaced tubular core II, and a pair of end cups or fittings I2 which are of identical shape. These ttings are spaced from each other in the longitudinal direction by the intervening core II, to the ends of which the fittings are brazed or otherwise secured so as to preserve the concentric relationship of the core II to the center tube 3. This makes a unit of the core II and the end fittings I2 which is slipped on to the center tube 3 and held in position by the two pipe couplings 5, 6. The remote ends of the fittings I2 are bevelled at I3 to make it easy for the plug to slide over corners, raised places, and joints in the pipe I.

The core II has one or more vent holes Il which are tapered inwardly as shown. An elastic sleeve I5 surrounds the core II, its periphery I6 normally being iiush with the cylindrical parts of the fittings I2. The sleeve I5 is preferably composed of rubber, but any equivalent elastic material will do as a substitute. In any event its ends IB are vulcanized or otherwise intimately connected with the adjoining and confronting faces of the fittings I2 so as to make absolutely tight joints past which pressure uid cannot escape.

Exceptlng for its sealed ends the elastic sleeve I5 is loose on the core II. The sleeve has projections I1 which match the form of the vent holes I4 and when the sleeve I5 is relaxed (Fig. 2) the projections I1 occupy the vent holes. The purpose in making the vent holes I4 of inwardly tapering form is to prevent pressure tluid being trappld between the elastic sleeve Il and the core The operation is readily understood. One can readily understand that upon securing a rod or corresponding contrivance l to one of the couplingsA 5, 6 the plug 2 can be wielded much on theorder as one would wield a swab in a boiler tube. The matter of determining how far to push the plug is something that does not have to be considered here. It is suillcient to understand that a portion of the pipe I is suspected of having a leak. Considering the leak to be in the portion of the pipe at the left oi' the plug 2 (Fig. l), after the plug has been located and expanded by pressure uid admitted through the check valve 8, other fluid under pressure is admitted to the pipe I at the left end of the pipe plug.

The pressure fluid now contained by the pipe plug escapes through the holes 9 into the chamber I0 where pressure is exerted upon the faces of the projections I'I. 'I'hese are immediately moved out of place, whereupon the internal pressure fluid enters the space I8 (Fig. 1), expanding the elastic sleeve I5 so that every part of it makes intimate contact with the bore oi' the pipe I.I

As pressure is built up, the sleeve I5 will press against the bore of the pipe all the harder, and

the uid separately applied to the left of thethe pipe.

It is desired to point out that the plug shown in the drawing is only one example' of how the principle ofthe invention can be embodied. In practice plugs will be used in singles. couples,

triples or more, depending on how the branches ot the conductor to be tested extend. It is easy to see that the pipe I can be tested in sections by using two identical plugs in spaced positions in the pipe. 'Ihe idea is to corinne the testing pressure between the plugs and as each section oi' the pipe is thus tested. the pair will be 'shifted on to a new place until the entire length ot the pipe has been traversed.

I claim:

l. A pipe plug comprising a center tube having a pair of end nttings spaced from each other and secured to the tube to form a unit, a tubular core having its ends secured to the end ttings, said core being spaced from the center tube to provide a chamber, said'tube having a hole communicating with the chamber and said core also having a hole, an elastic sleeve loosely encompassing the core, but having its ends permanently and tightly united with the end ilttings, and couplings connected with the center tube to hold the aforesaid unit in place on the tube and to provide for the attachment ot a wielding contrivance.

2. A pipe plug comprising a center tube, a unit mounted thereon, said unit consisting of end fittings and a tubular core spaced around the tube to provide a chamber, said tube having a hole communicating with the chamber and said core having a hole leading from the chamber, an elastic sleeve encompassing the core and being loose with respect thereto excepting at its ends which are premanently and tightly united with the end ttings, and projections cn the sleeve adapted to occupy the hole in the core, said hole being inwardly tapered to prevent the trapping of pressure iluid between the core and sleeve, and means carried by the center tube for both holding the unit in place and for coupling on a wielding contrlvance.

JAMES F. RICHARDSON. 

